This does have a few more complications than normal marriage/adjust status. You definately should be speaking directly with a good immigration attorney.
According to this document, if she arrived after February 2001, she should not be eligible for TPS. It says a Salvadorean entering after will be processed with the normal immigration laws.
http://www.uscis.gov/files/pressrelease/TPSQ_030201.pdf
I am unsure how she got the TPS...but if she is subject to the post 2001 rules, then she would have a very difficult time adjusting her status based on marriage, since she entered illegally.
If someone comes into the US legally, and overstays, they can adjust the status based on marriage. However, if they come illegally, then most likely will not be allowed to adjust status, and will be deported and subject to a 10 year ban on re-entry.
Here is a link to the process to adjust the status based on Marriage.
http://www.uscis.gov/portal/site/usc...0045f3d6a1RCRD

